“I was interested in this topic because our current knowledge of the factors underlying lifespan personality development is in its infancy. We know much about how some traits (such as conscientiousness and self-esteem) develop, but very little about other traits, like optimism,” said study author Ted Schwaba of the University of California at Davis.

“It seems sensible that optimism might change with age and that experiencing positive and negative life events can influence that development. So we set out to test that.”

For their study, the researchers repeatedly surveyed 1,169 Mexican American parents (ages 26–71) over the course of 7 years. The participants completed a measure of optimism and reported how often they had experienced 54 different positive and negative life events.

Schwaba and his colleagues found that optimism increased from ages 26 to 55 before leveling off. Participants who reported experiencing more positive life events, such as graduating from college and receiving pay raises, tended to become even more optimistic.

Surprisingly, experiencing negative events did not appear to impede the development of optimism over time.

“There seems to be a popular perception that people become less optimistic with age, that their maturity leads them to be better calibrated to the ups and downs of life. But it seems, in this sample and a few others, that the lifespan story of optimism is actually one of gradual increase throughout adulthood,” Schwaba told PsyPost.

“So, if you’re in your 20s and 30s, it’s likely that you’ll develop a rosier view of the world as you navigate the rest of adulthood, especially if you experience positive life events.”

The study — like all research — includes some limitations. In this case, the study’s sample could limit its generalizability.

“One important caveat to psychological research is to take caution when generalizing outside of the group that was studied. In this sample, we examined Mexican-American parents, which I think in many ways is great — far too often, we only study college-aged students primarily of European descent,” Schwaba said.

“But I would perhaps urge caution in extending this research to non-parents — this is speculating, but perhaps some of the normative optimism gains we found are tied to parents watching their children mature.”